The present invention relates to an auto-focus camera, and more particularly to an auto-focus camera having a capability for operation in a pinning mode.
Lens shutter cameras and single-lens reflex cameras having an auto-focus capability are usually adapted to measure the distance from an object to be photographed which is positioned by a photographer at the central portion of a view finder, i.e., at the center portion of an image area. Focusing is achieved in either a single AF mode (hereinafter referred to as an "S" mode) or a continuous AF mode (hereinafter referred as a "C" mode). In an S mode, the area of the object in which the photographer desires to achieve focus is brought into the range finding zone and the release button is partially depressed to bring the object in the center of the image area into focus. When focus is achieved, it becomes possible to release the shutter and the release button is further depressed to activate the shutter.
In a C mode, the release button is partially depressed and the object in the center of the image area is brought into focus. Unlike in the S mode, it is possible to release the shutter even if focus is not achieved. The photographer waits for the right time for releasing the shutter and in accordance with the change in the distance to the object, a focusing operation is performed and the release button is further depressed to activate the shutter.
There are two typical cases where focus is intentionally achieved other than in the focusing zone (range finding zone) of the image area. One is the case where shooting is done with focus achieved for an object located in the marginal portion of the image area, and the other is the case where with a certain location being preliminarily focused, shooting is done after confirming that the object has come to that location. In these cases, the following practice has conventionally been adopted. First, an AF mode selector means is set in the S mode and the object or location at which the photographer desires to achieve focus is brought into the focusing zone and the release button is partially depressed to achieve focusing. Then, with the release button kept partially depressed, the object is located in the desired marginal portion of the image area and the release button is further depressed to release the shutter.
The practice described above, however, has had the following problems. First, if the photographer releases the partially depressed shutter button, subsequent depression of the button will cause another focusing operation where an undesired object in the range finding zone may be brought into focus. To avoid this problem, the release button must be kept partially depressed until just before shooting is done. If the time when the desired object is brought to the intended marginal portion of the image area comes quickly, focusing in the S mode can be accomplished in a satisfactory way. However, if the right time for releasing the shutter does not come quickly, the release button has to be kept partially depressed for a long time, and this is a considerable inconvenience to the photographer. In addition, the associated electric circuit must be kept energized for a long time, leading to increased battery consumption.